1. Field of the Invention
Aspects of the present invention relate to a bi-phase platinum catalyst, a method of manufacturing the same, and a solar cell using the bi-phase platinum catalyst.
2. Description of the Related Art
Solar cells use solar energy. Well-known solar cells include silicon solar cells and dye-sensitized solar cells. Silicon solar cells are relatively expensive, thus are not suitable for practical use, and have difficulties with regard to improving cell efficiency. On the other hand, dye-sensitized solar cells are significantly cheaper than silicon solar cells, and thus, may replace existing amorphous silicon solar cells. Unlike silicon solar cells, dye-sensitized solar cells are photo-electrochemical solar cells, which include dye molecules that can generate electron-hole pairs by absorbing visible rays, and transition metal oxides through which the generated electrons are transmitted.
A dye-sensitized solar cell includes a counter electrode having a catalyst and an electrolyte having redox ion couples. The counter electrode having the catalyst functions to reduce ions, so that electrons can be continuously supplied to the cell.
The catalyst may be formed of platinum, carbon, a conductive polymer, or the like. Platinum has the highest efficiency. However, since platinum is very expensive, the platinum content of the catalyst should be minimized, so as to reduce the manufacturing cost of the solar cell, while maintaining efficiency.
In order to reduce the platinum content, a method of controlling a surface characteristic of the catalyst is used. In order to deposit the catalyst on a conductive substrate, a method of producing a platinum thin film, by dissolving a platinum salt in solvent, spin-coating the dissolved platinum to form a thin film, and then calcinating the thin film. An electroplating deposition method, and a sputtering deposition method have also been proposed. Among these methods, the method of producing the platinum thin film is the most economical. However, when using the method of producing the platinum thin film, it is difficult to control the surface characteristic of the electrode containing the catalyst, and to uniformly form the electrode containing the catalyst on a substrate surface.